73 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			73 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! This example illustrates how to add custom log layers in bevy.
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use bevy::{
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    log::{
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        tracing::{self, Subscriber},
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        tracing_subscriber::Layer,
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        BoxedFmtLayer, BoxedLayer,
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    },
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    prelude::*,
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};
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struct CustomLayer;
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impl<S: Subscriber> Layer<S> for CustomLayer {
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    fn on_event(
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        &self,
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        event: &tracing::Event<'_>,
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        _ctx: bevy::log::tracing_subscriber::layer::Context<'_, S>,
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    ) {
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        println!("Got event!");
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        println!("  level={}", event.metadata().level());
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        println!("  target={}", event.metadata().target());
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        println!("  name={}", event.metadata().name());
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    }
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}
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// We don't need App for this example, as we are just printing log information.
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// For an example that uses App, see log_layers_ecs.
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fn custom_layer(_app: &mut App) -> Option<BoxedLayer> {
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    // You can provide multiple layers like this, since Vec<Layer> is also a layer:
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    Some(Box::new(vec![
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        bevy::log::tracing_subscriber::fmt::layer()
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            .with_file(true)
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            .boxed(),
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        CustomLayer.boxed(),
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    ]))
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}
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// While `custom_layer` allows you to add _additional_ layers, it won't allow you to override the
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// default `tracing_subscriber::fmt::Layer` added by `LogPlugin`. To do that, you can use the
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// `fmt_layer` option.
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//
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// In this example, we're disabling the timestamp in the log output.
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fn fmt_layer(_app: &mut App) -> Option<BoxedFmtLayer> {
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    Some(Box::new(
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        bevy::log::tracing_subscriber::fmt::Layer::default()
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            .without_time()
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            .with_writer(std::io::stderr),
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    ))
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}
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fn main() {
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    App::new()
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        .add_plugins(DefaultPlugins.set(bevy::log::LogPlugin {
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            custom_layer,
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            fmt_layer,
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            ..default()
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        }))
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        .add_systems(Update, log_system)
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        .run();
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}
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fn log_system() {
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    // here is how you write new logs at each "log level" (in "most important" to
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    // "least important" order)
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    error!("something failed");
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    warn!("something bad happened that isn't a failure, but thats worth calling out");
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    info!("helpful information that is worth printing by default");
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    debug!("helpful for debugging");
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    trace!("very noisy");
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}
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